Showing papers by "Satoshi Yamamoto published in 1988"
TL;DR: In this article, the high-resolution vibration-rotation spectra of stable and unstable molecular species have been studied at low rotational and vibrational temperatures in a pulsed supersonic free jet.
Abstract: High-resolution vibration–rotation spectra of stable and unstable molecular species have been studied at low rotational and vibrational temperatures. Infrared absorption in a pulsed supersonic free jet has been measured by a frequency-tunable diode laser in a single- or multi-pass configuration. The modulated infrared absorption is detected by a lock-in amplifier or a two-channel boxcar integrator. The ν3 band of SiCl4 at 624 cm–1 is studied as one of the series of work on heavy non-polar inorganic compounds. Five spectroscopic constants are determined accurately for the ν3 band of 28Si35Cl4. Weakly bound molecular complexes are studied in the middle infrared region as unstable molecular species. Well resolved ro-vibrational spectra are observed in (N2O)2, C2H2·Ar, (C2H2)2, (C2H2)3, BF3·X (X = Ne, Ar, Kr), C6H6·X (X = Ar, Kr), and (NO)2 with Doppler-limited resolution. Infrared–microwave double resonance in a free jet is discussed for microwave spectroscopy of van der Waals complexes in vibrationally excited states.
27 citations
TL;DR: In this article, four rotational transitions of the H2Cl+ ion were observed in the frequency region of 270 to 500 GHz by using a source-modulated microwave spectrometer combined with a hollow cathode free space cell.
Abstract: Four rotational transitions of the H2Cl+ ion were observed in the frequency region of 270 to 500 GHz by using a source‐modulated microwave spectrometer combined with a hollow cathode free space cell. The H2Cl+ ion was generated by a dc discharge in a mixture of HCl, H2, and He. The ion was identified on the basis of the hyperfine structure of the chlorine nucleus. This was further confirmed by the observation of the line intensity decrease with external magnetic field, which is a characteristic of ions in a hollow cathode discharge. The rotational constants A, B, and C, and the centrifugal distortion constant ΔJK were determined. The nuclear quadrupole coupling constants of the chlorine nucleus were obtained for the first time: χaa =−53.44(47) MHz, χbb =−15.71(50) MHz, and χcc =69.15(70) MHz with three standard errors in parentheses. The character of the H–Cl bond orbital is estimated from the observed nuclear quadrupole coupling constants and the molecular structure.
18 citations
TL;DR: In this article, high-resolution vibration-rotation spectra of the two parallel bands ν14 and ν16 for cyclobutane were measured by a diode laser and FTIR spectrometers.
9 citations
6 citations
TL;DR: In this paper, an infrared spectrum of the ν16 band for cyclobutane was measured with a resolution of 0.03 cm−1 and the effective values of the barrier height and the equilibrium dihedral angle were estimated to be 649 ± 11 cm− 1 and 31.4 ± 1.3°, respectively.
Abstract: An infrared spectrum of the ν16 band (626 cm−1, CH2-rocking, A2u) for cyclobutane was measured with a resolution of 0.03 cm−1. Several Q branches of hot bands due to the ring-puckering mode (ν6, 198 cm−1, B2u) were observed. The puckering potential for the ν16 state was analyzed using a one-dimensional double-minimum potential, and the effective values of the barrier height and the equilibrium dihedral angle were estimated to be 649 ± 11 cm−1 and 31.4 ± 1.3°, respectively. Both of these values were larger than the corresponding values for the ground vibrational state, reported to be 510 ± 2 cm−1 and 28.8 ± 1.1°. The differences were ascribed to higher-order mixing between the ν6 and the ν16 modes; this mixing was analyzed by assuming a two-dimensional potential, and the barrier height and the equilibrium dihedral angle were reestimated to be 449 ± 9 cm−1 and 27.8 ± 1.2°, respectively.